ENVIRONMENTAL-FACTORS AFFECTING UNDERSTORY DIVERSITY IN 2ND-GROWTH DECIDUOUS FORESTS

The purpose of this study was to determine the most important nonanthr opogenic factors affecting understory (herbs, shrubs and low-growing v ines) diversity in forested landscapes of southern Indiana. Fourteen e nvironmental variables were measured for 46 sites. Multiple regression analysis showed significant positive correlation between understory d iversity and tree seedling diversity and soil subgroup. Slope aspect, soil rooting depth and number of standing dead trees were significantl y negatively correlated with understory diversity. Mesic sites were mo re diverse in common understory species than xeric sites but had lower total cover and different species.